University of Vermont Extension
Department of Plant and Soil Science

Fall News
Article

PREPARING ROSES FOR WINTER

Dr. Leonard Perry, Extension Professor
University of Vermont

Any discussion of how to help roses survive the vagaries of winter is
sure to initiate a lot of different opinions ranging from "do nothing"
to "bury plants completely" or "it can't be done!" Personally, I believe
many roses--namely shrub roses--can survive in cold climates with a little
winter protection.

Roses can be killed or injured during winter in several ways: direct
injury to tops or roots from extreme cold; rapid temperature changes; root
injury from dry-out as a result of plants being heaved by alternate freezing
and thawing; injury caused by mice under snow; and snow or ice breakage.

Injury from extreme cold can be avoided only by selecting hardy varieties.
As a rule, roses with small blossoms tend to be hardier than the largest
flowering types. Most hybrid tea varieties are less hardy than the grandifloras
or floribundas. In addition, some climbing roses and many old-fashioned
bush varieties tend to be hardy as are some series such as "Explorer" out
of Canada. Hardiness depends on variety and type. However, this is based
more on observation than actual hardiness studies, so gardeners must be
willing to take chances and experiment with different varieties. But the
good news is that proper winter protection can help plants survive.

For bush varieties, start by mounding soil 10 to 12 inches around the
base of the plants. Then add another 12 to 16 inches of mulching material
such as leaf mold, straw, hay, or pine needles over the mound to help stabilize
soil temperatures. This extra protection means less freezing, thawing,
and subsequent heaving. If you have many rodents around, you may
want to skip the mulch materials as they provide a winter home for unwanted
wildlife. Ideally, mounding should be applied in mid to late November.
Earlier application may slow development of stem maturity and hardiness.

You may need to prune the canes back to the surface of the mulch for
ease of covering, but don't cut back any further. Wait until spring, so
you can see which canes or parts of canes have died, then cut them back.
If the winter is mild, or your mulching thick, you may have to cut back
very little.

Climbing roses survive the winter best when you remove the canes from
the fence or trellis and fasten them to the ground. Snow cover will protect
them from extremely low temperatures. Where snow cover is undependable,
mound snow or mulch over the canes on the ground. Remove the mulch as plants
start to grow. Earlier removal may cause the rose stems to dry out. The
common practice of wrapping stems and trellises with straw and paper or
burlap provides, at most, a few degrees of protection on cold nights. It
is less dependable than protecting stems with soil on the ground. You can
also make a frame to catch snow if snow cover is reliable in your area.

Remember, these precautions will not always ensure survival and prevent
injury. However, they usually will enable northern gardeners to grow some
of the less hardy roses.